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Bought a 2018 s40 Boulevard with 685 miles on it. Rode it home with choke all the way open (d'oh!) and left it that way overnight. Gas on the floor the next morning. Dealer picked it up, put in a new carb, and all was well... for a little while. Not long after, was taking a long time to start and sometimes didn't start at all. I bought and installed a new spark plug and a new battery. Started right away and ran good... for a couple miles. Then, kept killing/dying. Made it home after pulling over several times and restarting. After leaving it in the garage for a few days, now it won't start at all. Has 1,000 miles on it. So - new carb, new plug, new battery. I pulled out the vent hose to the carb - no blockage. Gas tank is venting fine too.

Ideas? Suggestions?
 

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I would contact the dealer again surely you have some sort of warranty. If not check the state of the battery charge....even new ones can fail. Also check for any draw with the ignition off. Check for spark....you may have an electrical fault that is either intermittent or affected by heat, although since it wont start at all it would appear whatever the fault is it is now continuous.

If the plug is wet then there is no spark...if dry then its fuel supply. You only need three things for it to run....fuel, spark and air.

Check any fuel filters etc...does this bike have a fuel pump? if so is it running... does it supply a good flow....easy to check just pull the fuel pipe from the carb....same applies for a non pump bike....you may have a blocked/faulty fuel valve....if its a vacuum operated one then the vacuum port may be blocked or the pipe kinked...same with the fuel delivery pipe....had a Bandit that had to have the pipe in a slight downhill position or it would starve for fuel.

One final thing do you use the kill switch to shut it off. I never use them....they can cause all sorts of problems.

good luck
 

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Discussion Starter · #3 ·
I would contact the dealer again surely you have some sort of warranty. If not check the state of the battery charge....even new ones can fail. Also check for any draw with the ignition off. Check for spark....you may have an electrical fault that is either intermittent or affected by heat, although since it wont start at all it would appear whatever the fault is it is now continuous.

If the plug is wet then there is no spark...if dry then its fuel supply. You only need three things for it to run....fuel, spark and air.

Check any fuel filters etc...does this bike have a fuel pump? if so is it running... does it supply a good flow....easy to check just pull the fuel pipe from the carb....same applies for a non pump bike....you may have a blocked/faulty fuel valve....if its a vacuum operated one then the vacuum port may be blocked or the pipe kinked...same with the fuel delivery pipe....had a Bandit that had to have the pipe in a slight downhill position or it would starve for fuel.

One final thing do you use the kill switch to shut it off. I never use them....they can cause all sorts of problems.

good luck
Thank you, Aussie Steve. Several things for me to check here.
 

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Thanks, Easy Rider. Yes, it has a Prime setting. The other day, it basically only ran when in that setting. But now I can't get it started at all.
OK, then that also means that there is a vacuum line going from the carb(s) to the petcock.

If that line is open or cracked, it will make a HUGE vacuum leak into the manifold AND shut off the automatic valve.

A similar thing can happen if the diaphragm inside the petcock has a leak.
Sometimes that will make it lean due to a vacuum leak.......and sometimes raw gas will be sucked in through the damaged valve.
 
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